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By A. Koning, P. Lauzon

Pressure hydrometallurgy operations require vessels to be lined with an impermeable membrane for corrosion protection and one or more courses of refractory or ceramic brick. Examples of unit operations that utilize composite lining systems include pressure oxidation autoclaves, sulphide precipitation autoclaves, chloride leach reactors, flash vessels, cyclone separators, and direct contact condensers (heater vessels and quench vessels). The refractory lining must satisfy multiple requirements: it must thermally insulate the membrane from process fluid, be structurally stable, provide erosion resistance, be chemically compatible with process fluid, and provide an economic service life. New hydrometallurgical processes are pushing the pressure, and temperature, with each new generation of plants. A fundamental understanding of all factors affecting the mechanical stability of the lining system is essential as lining designs move further away from the industry's experience base. The impact of irreversible chemical swell, operating factors, design factors, and installation factors are presented based on modifications to the traditional one-dimensional mechanical stress model. A new stability criterion - that the brick lining remain in contact with the steel shell membrane - is presented. This new stability criterion imposes new restrictions on the lining design.The effect of geometry and adding additional degrees of freedom to the analysis is explored using two-dimensional and three-dimensional Finite Element Analysis (FEA). The effect of these additional degrees of freedom on the results of the one-dimensional model are discussed.

Jan 1, 2004

By M. Souley, G. Armand, M. Ghoreychi, D. Seyedi, J. -B. Kazmierczak

"An anisotropic constitutive model is proposed in this paper accounting for both structural anisotropy and induced anisotropic plasticity. It is assumed that the rock is composed of a matrix and of potential planes of weakness. The matrix is assumed to be linear, transversely isotropic and the plasticity is described by a non linear yield function where the parameters are deduced from the nonlinear Hoek-Brown envelopes in pre- and post-peak, and derived from the laboratory characterization. A non-associated flow rule is used with a distinction between compression and extensional stress paths, as well as the absence of volumetric strain beyond large plastic distortion.The planes of weakness are considered as known a priori or assumed to be oriented perpendicular to the direction of the current minor principal stress. An elastic-perfectly plastic behavior according to the Mohr-Coulomb criterion is assumed in the planes of weakness; while the elastic part is considered as linear and transversely isotropic.Finally, the proposed model was implemented in FLAC3D and used to simulate triaxial compressions to provide a verification of the implementation. The applicability of the implemented model to reproduce damage (pre-peak) and/or failure developments around a circular opening is checked. The GCS drift, one of the mine-by experiments set up at the main level of the Meuse/Haute-Marne Underground Research Laboratory, is selected for this first application."

Jan 1, 2015

By Ron Zevenhoven

In Finland one opportunity for large-scale CO2 capture, utilisation and storage (CCUS) is CO2 mineralisation, i.e. mineral carbonation. A process route under development towards industrial application involves production of magnesium hydroxide or sulphate from serpentinite rock (serpentine = 3MgO·2SiO2·2H2O), followed by conversion either in a pressurised fluidised bed (PFB) reactor, giving magnesium carbonate, or in an aqueous solution process giving magnesium hydro-magnesites. Iron present in the rock is typically obtained FeO(OH). Results obtained with these process routes and progress towards industrial demonstration is addressed, process heat integration and operation on flue gases (without CO2 pre-separation!) being key features for economic viability. A process route utilizing calcium-containing slag by-product from iron- and steelmaking under development towards large-scale application is the so-called slag2pcc concept. It converts an industrial by-product into valuable material, reduces use of natural material and streams to landfills while binding CO2 produced by the process generating the slag. Using ammonium salts, calcium is extracted from steel converter (BOF) slags and subsequently carbonated in a two-stage aqueous process (at ambient temperatures and pressures). Precipitated calcium carbonate (PCC) is produced while regenerating the ammonium salt. Process performance and scale-up while guaranteeing a certain PCC quality are presented.

Jan 1, 2015

By T. Sakai

Present authors have succeeded in single pass large draught rolling of AZ31 and ZK60A magnesium alloy sheets below 200 °C without heating rolls by raising rolling speed above 1000 m/min. Heavy reduction larger than 60% can be applied by single pass high speed rolling even at room temperature. The rolled sheets showed fine recrystallized microstructure by dynamic recrystallization. The improvement of workability at lower rolling temperature is due to temperature rise by plastic working. In high speed rolling, almost all of the work done by plastic deformation is converted into the heat that raises the temperature of the sheet during rolling because the heat did not flow out of the sheet by conduction and radiation within very short time.

Jan 1, 2006

By G. W. Clark

"The mining of the ore bodies at Rabbit Lake has in the past been by the open pit method. This method is presently being used to develop the B-zone and will continue into the future with the development of two smaller ore bodies, the A-zone and D-zone. The Eagle Point orebody will be developed by an underground method which will provide production and employment into the next century.The ore bodies at B-zone, A-zone and D-zone are unique in that they are located under Wollaston Lake. To permit mining by the open pit method a steel-celled dyke has been constructed around the north end of the B-zone. This same dyking method will be used for the A -zone and D-zone. INTRODUCTIONMine development at Rabbit Lake commenced in 1970when a detailed engineering feasibility study established the viability of the Rabbit Lake deposit. In 1972 construction of the mill and camp site began. Construction materials were seasonally hauled to the site over a winter road until November 1973when the government of Saskatchewan completed an all-weather road to within six miles of the operation.In October 1974, stripping of the Rabbit Lake open pit began with the removal of overburden and lake bottom sediments from the previously drained Rabbit Lake. The first ore was processed by the mill in June 1975and by October the mill was producing three million pounds per year. The design capacity of five million pounds annually was first achieved in 1977 and maintained until 1981, when lower ore grades resulted in lower production rates .It was clear when mining at Rabbit Lake began that, without additional reserves, the Rabbit Lake operation had a life of less than 10 years. Exploration, therefore, continued in the immediate area in an attempt to discover additional uranium mineralization."

Jan 1, 1989

By C. H. Lau, I. T. Ng

Uniaxial Compressive Strength (UCS) of rocks is an important mechanical parameter for many civil engineering and rock engineering applications such as tunnel excavation, slope stability and foundation design. Macau is one of the world's fastest growing and most densely populated cities, many large and important infrastructures have been being continuously built using pile foundations which are designed to be supported by granitic bedrock. In Macau, the UCS of the granitic bedrock is required almost for every project involving pile foundations and is always measured directly from UCS test in the laboratory. However, direct measurement of UCS requires high quality rock core sample which is not only time-consuming and expensive but also requires high level of operating skill. In view of this fact, estimation of UCS using some empirical correlations will be more practical and efficient because they are relatively fast and economical compared to the direct measurement from UCS test. In the past, some empirical correlations had been established and widely used for estimating UCS of rocks in common engineering practice. However, it has been well recognized that the rock properties are generally varied with sites or geological regions in other words an empirical correlation developed from one region or one country may not be applicable for other regions or countries. Due to the reason that the empirical correlations for predicting UCS for granite are scarce in practice, in this study an extensive experimental program has been performed and a large database containing data such as UCS, Point Load Index (Is50), Schmidt Rebound Hardness (RL), porosity (?), water absorption (S), specific gravity (Gs) and dry density (?d) has been developed. An attempt has been made for developing a new empirical correlation for estimating the UCS of Macau granite. Accordingly, a comprehensive statistical analysis for correlating UCS with Is50, RL, ?, S, Gs and ?d has been performed and a local empirical relationship based on the developed database is proposed for obtaining reliable estimation of UCS for the granite of Macau. Finally, the performance of the proposed correlation is accessed by using another independent testing database developed in this study. It indicates that Is50, RL, ? and S have strong correlation with UCS whereas Gs, ?d have poor correlation with UCS. This study not only proposed a proper predictive empirical correlation for UCS determination for Macau granite but also provides detailed statistical information which is beneficial to engineers for obtaining better characterization of Macau granite.

Jan 1, 2015

By C. Kuehmann, B. Tufts

QuesTek Innovations has applied its Materials by Design® methodology to computationally design a new ultra high-strength corrosion resistant steel. Ferriurn® S53 eliminates the need for toxic cadmium coatings currently used on conventional steels in landing gear systems. S53 has the strength of 300M steel, and corrosion resistance similar to 15-5PH stainless steel. S53's corrosion resistance improves stress corrosion cracking resistance and reduces susceptibility to hydrogen embrittlement, improving component reliability and providing an opportunity for extended overhaul and repair intervals. Ultimate tensile stress is 1965 to 2000MPa. S53 was designed to be mechanically equivalent to 300M, with the key addition of intrinsic corrosion resistance. Alloy design, microstructural characterization, and mechanical properties are discussed herein.

Jan 1, 2006

By G. W. Poling

"Construction, equipping and planned operation of a new laboratory for engineering-teaching and research in coal and mineral processing is described. This facility will provide approximately 1860 m2 (20,000 ft. 2 ) of laboratory space with nearly half devoted to a new venture in coal preparation. Two high-bay, overhead crane-accessed areas will accommodate major unit operations for each of the ""coal"" and ""mineral"" laboratories. COAL PREPARATION FACILITIES:The coal facility provides three main functional areas:(1) Sample preparation (drying, blending, crushing, screening) and sink-float washability testing.(2) Unit operations U1igh-bay, serviced by crane).(3) Analytical laboratories.(l) Sample Preparation and Sink-Float TestingBreaking or comminution of coal will be accomplished using a rolls crusher, a hammer mill, a jaw crusher, or a pulverizer. Capacity to prepare coal at rates of up to approximately 4 tph will be provided by some of these units. Large diameter (~0.5m) baths of heavy organic liquids will be available for sink-float washability tests on coal samples of several kg. Particle sizes of up to 25 mm can be tested in these baths. Smaller scale washability tests on finer samples will be accelerated by centrifuges."

Jan 1, 1980

By G. D. Ruttan

"LYNN LAKE, in northern Manitoba, has become Canada's second nickel-producing area. The discovery by Sherritt Gordon Mines of nickel ore in an entirely new district was the result of systematic prospecting of a belt of volcanics and sediments situated 100 to 150 miles north of the Company's former copper-zinc mine at Sherridon, Manitoba.Prospecting in this area was begun in 1937 and continued each year until 1941, when Austin McVeigh, a company prospector, found a patch of sulphides on a gabbro outcrop near a small lake named Lynn Lake. Samples from this sulphide indicated nickel and copper in significant amount. In 1943, magnetometer work disclosed a number of weak anomalies in low ground near the discovery. In 1945, staking was followed by geophysical surveys and diamond drilling, which continued through 1947. During this period the A, B, E, EL, and Corebodies were located and partly outlined. The discovery of the high-grade ""EL"" orebody in January 1947 was the turning point in the estabishment of the mine. Subsequent development, including additional exploration on surface and under-ground, evolution of a new metallurgical process, financing, erection of a mining and milling plant, hydro-electric power development, building of a rail line from Sherridon (by Canadian National Railways) and a refinery at Fort Saskatchewan, Alberta, culminated in August 1954, when the first shipment of nickel left the refinery. This paper, presented at the 1955 Annual General Meeting of the C.l.M. in Toronto, was one of a symposium covering the whole operation."

Jan 1, 1949

By J. J. Ferreira, M. L. Thurston, I. L. Chinn, D. M. Rose

"Concerns about using microdiamonds for resource estimation have been raised by workers because multiple diamond populations exist in many parts of the mantle source region, small diamonds in kimberlite could be exposed to proportionately greater levels of resorption and modification, and euhedral microdiamonds could crystallize immediately prior to kimberlite eruption. This paper addresses these concerns; discusses the geology of the mantle, the principal diamond host rocks, and the impact of mantle processes; compares micro- and macrodiamond properties and features; and outlines steps to identify and mitigate the risk of diamond resorption and its impact on the diamond grade-size relationship.RÉSUMÉ Des travailleurs se sont interrogés sur l’utilisation de microdiamants pour estimer la ressource; en effet, de multiples populations de diamants existent dans plusieurs secteurs de la région source dans le manteau. Des petits diamants dans la kimberlite pourraient être exposés à des niveaux proportionnellement supérieurs de résorption et de modification; de plus, des diamants idiomorphes pourraient cristalliser immédiatement avant l’éruption de la kimberlite. Le présent article traite de ces questions, discute de la géologie du manteau, des principales roches-mères des diamants et de l’impact des processus dans le manteau, compare les propriétés et les caractéristiques des micro- et des macrodiamants et définit les étapes pour identifier et mitiger le risque de résorption des diamants et son impact sur la relation entre la taille et la qualité des diamants."

Jan 1, 2016

By L. C. S. Dharmasiri, S. M. Shin, A. Senaputra, J. S. Sohn, K. H. Park, J. Avraamides

Reducing agents can be applied to leach metal values from natural and secondary resources such as laterite ores and deep sea manganese nodules and recycled materials such as spent batteries / catalysts which contain high-valent metal oxides of manganese, cobalt and iron. Selective leaching of some metals can be achieved by selecting conditions to control the saturated solubility and dissolution rates of metals from oxides or mixed metal/oxide matrices. The leaching results are rationalized on the basis of chemical species, Eh-pH diagrams and heterogeneous kinetic models. The role of reducing agents such as hydrogen peroxide, sulfur dioxide and iron(II) sulphate, in acid, alkali and in the presence of complexing ligands such as ammonia for the improvement of the leaching of metal oxides and metals is discussed. Previous studies on acid leaching of metals from nickel laterites, manganese nodules and spent catalysts/batteries in the absence or presence of reducing agents show that the rate controlling step involves the diffusion of protons through a thickening product layer on the particle being leached. It is shown that the leaching of nickel and cobalt from manganese nodules and zinc-carbon batteries in ammoniacal sulphur dioxide solutions also obey shrinking core kinetics.

Jan 1, 2014

By D. A. MacLeod

DURING the past fourteen months, dust surveys have been made at thirty-six mines in the Province. These surveys are made to determine the concentration of dust in the mine atmosphere, the flow of air through the mine, the methods adopted to prevent the generation of dust, and the measures taken for its elimination. When high concentrations of dust are encountered, suggestions are given for its prevention ?and elimination wherever possible. Dust sampling is absolutely necessary to determine the effectiveness of any measure taken in the prevention and elimination of dust in the mine workings. Consequently, more time has been spent on this phase of the work than on any other. The apparatus used is the Devers circular konimeter and Zeiss microscope. At various mines, the Zeiss konimeter is used, and the dust counts taken by the two instruments have given results that are closely comparable; so much so that either instrument can be used with confidence and the results obtained will compare in accuracy with those obtained by the methods used in Ontario and South Africa. Before the Workmen's Compensation Act Amendment Act was passed in November, 1936, most of the mine operators were already keenly interested in the prevention of silicosis. This interest has been intensified at all the mines, and measures have been adopted to decrease the amount of dust in the mine atmosphere. Several operators have spent a large amount of time and money in bettering these conditions, and have met with decided success. Practically all others are adopting the known methods of prevention, suppression, and elimination of dust, that apply to their ?particular mines. To prevent the production of dust in underground workings should be the first, as it is the most important, aim, especially during the time the men are underground. An atmosphere free of dust cannot be obtained, but measures can be adopted to lower the concentration that is found? in the average mine.

Jan 1, 1939

By Y. G. Yaroshenko, V. Y. Baldin, Y. M. Gordon

The manufacture of sulphuric acid from the off-gas of pyrometallurgical processes in the production of heavy metals is one of the common methods of effective recycling of sulfuric anhydrite. The new Impact-Inertial Devices with the rectangular contact channels (IIRCh) and the internal circulation of liquid allow the injection of an absorber into the phase's interactive cell by utilizing the gas stream energy and by this way increasing the sulphuric acid yield and reducing the power consumption. These devices have the following advantages: simplicity of design, smaller size, low capital expenses, absence of irrigating system, high operational reliability, simultaneous cleaning of solid, gaseous and liquid impurities and also cooling of gases etc. The IIRCh efficiency is almost 18 % higher and they require 1.3-2 times lower energy when compared with Venturi Absorbers. Also the elevation of spraying nozzles or injectors is 1.5 times lower in the IIRCh case.

Jan 1, 2004

By Q. H. Bui

The elastoplastic self-consistent model is one of the effective models to study the initial microstructure effect on the mechanical behavior of bulk materials. However, the use of this micromechanics-based model which takes into account only the Hall-Petch relationship at grain level for predicting the grain sized effects on the strength of the deformed materials is not accurate yet because of the fact that the dislocation density contributes also to the strengthening of this kind of materials. In this study, a modification made to the Hill-Hutchinson elastoplastic self-consistent model was proposed for investigating the microstructure dependence of the mechanical behavior of cold-drawn 6063 aluminium tubes. Because of the novel modification, an estimation procedure with two steps was required to identify the parameters of this micromechanical model. An acceptable agreement between experimental and theoretical stress-strain curves was achieved.

Jan 1, 2011

By Guoxiang Chi

The Cornwallis Fold Belt in the Canadian Arctic Archipelago contains numerous Mississippi Valley-type (MVT) Zn- Pb occurrences and the world-class Polaris deposit. The occurrences are mainly hosted by the dolostone in the Thumb Mountain Formation which spreads over 25000 km2. Success in exploration requires further understanding of the genesis of these occurrences and an assessment of their parentage with the giant Polaris deposit. Syn-sulfide dolomites in regional occurrences share C-O-Sr isotopic characteristics similar with Polaris dolomites, indicating warm basinal brines enriched in 87Sr. The dolomites and sphalerites contain fluid inclusions with ice-melting temperature between ?45° and ?25°C, which is significantly lower than for most MVT districts in the world (?30° and ?10°C). These characteristics indicate that all the Cornwallis occurrences were produced by fluids of the same sources and/or aquifers. The deposit size was largely controlled by the rate and duration of the metal-carrying fluid flow, and by the availability of reduced sulfur at the site of mineralization.

May 1, 2001

By Thomas Kilpatrick

The liability created by building this railway is the great financial problem before the people of British Columbia at the present time. In dealing with the subject, I propose to divide it into three periods: The Past - The Present - and The Future. The Past The primary objects in building the railway were to provide an independent and direct route for the Grand Trunk Pacific railway into the city of Vancouver, and to open the central and north-eastern portion of the province.. This vast territory, almost one-half the entire area of British Columbia, has great wealth in fruit, agricultural, and grazing lands; timber, coal, water-power and minerals of all kinds, including some of the richest placer deposits in the world. Rivers and lakes teem with fish. Big game, including moose, elk, caribou, deer, grizzly and black bear, mountain goat and sheep, is plentiful and there is an abundance of small game and fur-bearing animals. In addition, its scenic attractions are unsurpassed in Canada. To develop these resources it was considered necessary to build a railway from south to north as a main artery of transportation and, if necessary, branch lines to carry heavy .shipments of coal or other commodities. Lighter freight may be handled by motor trucks from distant points to the railway.

Jan 1, 1925

By L. Bichler

Lightweight magnesium alloys are gaining in popularity for applications in the automotive and aerospace industries, Their use, however, remains limited due to their relatively low strength and creep properties. Lost Foam Casting (LFC) is a new casting process and the strength of foam cast magnesium alloys has not been investigated in great detail thus far, In this research, magnesium alloy AZ91 E and three new alloys were cast by the LFC process to study the effect of varying aluminum and manganese content on the alloy's tensile properties, The study reveals, that the tensile strength of the magnesium alloy is closely related to the relative amount of aluminum in the system. Formation of ß-Mg17Al12 phase was seen to significantly affect the yield strength and ductility of the alloy, Furthermore, formation of manganese intermetallic compounds was seen to effectively increase yield strength of the base alloy, Individual alloy morphologies were analyzed via optical and SEM techniques.

Jan 1, 2004

By William G. Pariseau

"This contribution describes linkage of stress concentration at the face of tabular excavations, for example, longwall coal mine panels, at a meter scale to surface subsidence at a kilometer scale. Joints are considered according to orientation and spacing at an intermediate scale. A new dual-node, dual-mesh technique based on first principles uses a multi-scale technique that allows for computing whole mine surface subsidence while also allowing for computational details of stress, strain and displacement about main entries and pillars, panel entries, and bleeder entries. The technique is implemented in a conventional continuous Galerkin finite element program that has been in use for many years.The advantage of the dual-node, dual-mesh technique is the capability to do a whole mine analysis that takes into account interaction between all sections of a mine where stress transfer over long distances is often the rule rather than the exception while at the same time allowing for details of stress concentration at working faces where caving is initiated and subsidence begins. The technique, outlined recently during ARMA 2014 (Pariseau, 2014), is applied to an underground coal mine in central Utah where mines are developed from outcrops in steep canyon walls. Meshes contain over 10 million, three-dimensional nodes; runtimes are typically overnight, as a practical matter. Results compare favorably with mine subsidence measurements made over a period of several years and show the capability of this new technique to provide useful design guidance for tabular deposits such as underground coal mines. The role of variability or uncertainty in strata properties is illustrated in element safety factor distributions about development, bleeder and main entries and pillars. Such details are new in this contribution. Energy tracking for mine-induced seismicity is also new. Results show a high correlation between number of events and failed elements and suggest a simple index to mine induced seismicity."

Jan 1, 2015

By H. L. Cheng, C. H. B. Leitch, C. T. Hood, A. J. Sinclair

"Epithermal Zn-Pb-Cu-Ag-Au quartz-carbonate-barite veins at the Silver Queen mine near Owen Lake, west-central British Columbia, are hosted by Late Cretaceous Tip Top Hill andesitic volcanic rocks. The veins form a rectilinear northwest-northeast pattern that differs slightly from regional structural trends. The main northwest-trending veins are oriented very close to the trend of regional northwest faults, but the crossing veins tend to be more east-north-easterly (070 degrees)compared to a regional north-easterly trend (040 degrees). The character of the veins suggests they are extensional features formed by dextral slip related to Paleogene oblique subduction, or intrusion of magma at depth, or both.In detailed exploration at the mine, the veins cannot be modelled as simple tabular sheet-like bodies. Instead, they are complex structures that divide and rejoin, forming multiple veins or stringers, or are found in shear zones as replacement features with quartzsericite- clay-carbonate-pyrite alteration haloes of variable width that make definition of vein margins and correlation from hole to hole ambiguous. In addition, individual veins within each of the main structures have en echelon characterboth along strike and down dip.Geological and assay data must be carefully studied to define the margins of these complex veins before any estimation of ore reserves may be made. Where multiple veins occur in a section, ore/gangue mineralogy, assays, character of wallrock alteration, and thickness of vein and mineralized hangingwall, median and footwall zones must be used to evaluate continuity of mineralized structures. Well-defined sections are projected into areas of increasing complexity. Once the vein boundaries are defined, metal concentrations, important metal ratios(Au/Ag, Pb/Zn, Cu/Zn), and true thicknesses of the vein provide the basic data for reliable ore reserve estimation."

Jan 1, 1991

This document presents estimates of future "total cash cost per ounce" and "minesite cost per tonne" that are not recognized measures under United States generally accepted accounting principles ("US GAAP"). This data may not be comparable to data presented by other gold producers. These future estimates are based upon the total cash costs per ounce and minesite costs per tonne that the Company expects to incur to mine gold at the applicable projects and do not include production costs attributableto accretion expense and other asset retirement costs, which will vary over time as each project is developed and mined. It is therefore not practicable to reconcile these forward-looking non-GAAP financial measures to the most comparable GAAP measure. A reconciliation of the Company's total cash cost per ounce and minesite cost per tonne to the most comparable financial measures calculated and presented in accordance with US GAAP for the Company's historical results of operations is set forth in the notesto the financial statements included in the Company's Annual Information Form and Annual Report on Form 20-F, for the year ended December 31, 2009, as well as the Company's other filings with the Canadian Securities Administrators and the SEC.

May 1, 2011